alleryAn object placed at the focal point of a convex lens produces image:
AAt 2F
BAt the optical centre
CAt the same point as the object
DAt infinity
Answer & Solution
Correct answer: D. At infinity
1. Use 1/v - 1/u = 1/f with u = -f.
2. 1/v = 1/f + 1/u = 1/f - 1/f = 0.
3. So v is infinity (rays leave parallel).
4. Hence image forms at infinity.
_Source: Selina Concise Physics ICSE Class 10, Ch 5 'Refraction through a Lens' (aplustopper.com extract)_
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